Browsing by Author "Muriuki, A.W."
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Item Manures in African Smallholder Farming Systems: A Review(2013) Muriuki, A.W.; Mureithi, J.G.; Lekasi, J.K.; National Horticultural Research Centre, KARI-Thika), P.O. Box 220-01000, Thika, Kenya.Agricultural development in Sub Saharan Africa (SSA) is faced with a growing soil productivity crisis due to deterioration of the soil capital base, which is caused by among other reasons, greater removal of nutrients in crop harvests than those returned each year. Unlike other continents where intensification of crop production has been made possible through increased fertilizer usage, widespread use of fertilizers in Africa is still hampered by high commodity prices, poor infrastructure, a lower proportion of irrigated land compared to other continents, reliance on traditional crop varieties that are less responsive to fertilizers and increasingly unpredictable weather patterns due to climate change. Soil fertility replenishment therefore relies heavily on application of organic resources (where available), which benefit soil primarily by building up soil organic matter. Animal Manures though widely used by smallholder farmers are of low and variable quality, and bulky. This restricts application to homestead fields, in the process, aiding the creation of within-farm soil fertility gradients after repeated applications. On the other hand, green manures though effective have a high demand for labour, compete for land and moisture with crops, and seeds are scarce. Experts however, advocate combined use of organic and inorganic nutrient sources usually referred to as Integrated Soil Fertility Management (ISFM) because the relative nutrient compositions of organic resources do not normally match crop requirement ratios and neither do their nutrient release patterns commonly synchronize with crop demand. Future research needs should focus on increasing organic resource use efficiency through synchronization of nutrient release patterns with crop demand, increasing the concentration of nutrients in animal manures through innovative management techniques that improve efficacy and reduce bulkiness, developing whole-farm soil fertility recommendations to diminish formation of within-farm soil fertility gradients, and on studying the long-term effects of organic resources on soil properties, crop. Productivity and the environment within the context of climate change in SSA.Item Organic and Conventional Farming Systems Effect on Soil Properties: A Review(Target Publishing, 2021-12) Kibet, J.; Mucheru-Muna, M.W.; Muriuki, A.W.; Kenyatta University ; Kenya Agricultural and Livestock Research OrganizationFood security is of significant concern in developing countries. Increasing global population, consumption rates, shrinking of the available land and declining soil fertility are putting pressure on viable agricultural land and natural resources to attain food security. Therefore, conventional production system is practiced to meet the potential yield of food requirements. Scientists, organizations and policy makers emphasize on practicing organic farming system as an alternative for high productivity and high-quality agricultural products on a sustainable origin, and high- quality food could be produced through organic practice without affecting the environment. Agricultural intensification through conventional farming systems have proved to increase yield in the short-term but in the long- run jeopardized soil fertility through loss of viable soil nutrients. Despite conventional farming increasing yields, over the past 10 years, enormous controversy has raged over the use of fertilizers and pesticides and its impact on the environment. Another debate on the concern whether organic farming can feed the sharply fast-growing global population has been of the recent topic of discussion. Organic farming when given enough time can be able to produce sufficient food to curb food insecurity. Organic farming practice in Africa and other developing countries is still facing the challenge of production of sufficient biomass for organic inputs. Conventional farming without amendments cannot help in achieving agricultural sustainability.Item Overcoming Soil Acidity Constraints Through Liming and Other Soil Amendments in Kenya: A Review(East African Agricultural and Forestry Journal, 2022) Esilaba, A.O.; Mangale, N.; Kathuku-Gitonga, A.N.; Kamau, D.M.; Muriuki, A.W.; Mbakaya, D.; Zingore, S.Food production in Kenya is constrained by low and declining soil health resulting from low soil fertility and increasing widespread soil acidity, coupled with emerging climate change effects leading to recurrent food and nutrition insecurity. The major food production areas with high crop yield potential in the country are greatly affected by soil acidity due to continuous cropping, loss of organic carbon, nutrient leaching and inappropriate use of fertilizers. While use of organic and inorganic fertilizers, improved seed varieties and crop protection have received much research attention, liming as one way of improving soil health and crop production has not received similar attention. Consequently, potential yield of hybrid crops remains constrained. Soil acidity is mainly ameliorated by applying lime or other acid‐neutralizing materials, which neutralize the acidity, raises soil pH, increases the availability of plants’ nutrients and adds calcium and magnesium to the soil. It also improves the environment for beneficial soil microorganisms thus enhancing rapid breakdown of organic materials in the soil and releasing nutrients for growing plants. Soil buffer capacity determines the amount of lime per unit of soil volume needed to alter soil pH. Soils with low Cation Exchange Capacity (CEC) respond rapidly to liming than soils with high CEC. But the low-CEC soils have a high capacity for rapid leaching of the added bases, thus a quicker return to original acidity unless additional liming is done. Over-liming is recommended for soils which have low CEC, such as sand which is deficient in buffering agents such as organic matter and clay. There is therefore need for appropriate attention to to ameliorate soil acidity in order to maintain good soil health for food and nutrition security. A meta-analysis of a desk study supported by field experiment was carried out in areas viewed as most affected by soil acidity. The aim of the study was to evaluate amendments that can be used for alleviating soil acidity in acidic soils. The results showed that extensive work has been done in Western and Rift valley regions of Kenya targeting soil acidity alleviation and few studies in the coastal and eastern regions due to perception that these areas do not have acidic soils. Among the soil acidity amendments, use of lime and organic sources showed positive crop response and increased yields when applied in acidic soils.Item Plant Water Relations Of Bambara Nut (Vigna Subterranea L.) And Groundnut (Arachis Hypogaea L.)(University of Nottingham, 1990) Muriuki, A.W.Two tropical drought tolerant legumes, bambara ground nut (Vigna subterranea) and ground nut (Arachis hypogaea) were grown in the controlled-environment glasshouses at the University of Nottingham, School of Agriculture, UK. Water relations of the leaves i.e. water potential (1/11)' osmotic potential (1/;7r)' turgor potential (1/1 p) and relative water content (RWC) were determined for both species under three watering regimes:- 'dry', 'intermediate' and 'wet'.Item Proceedings of the KARI-NARL-Fertilizer Use Recommendation Project Proceedings Training Workshop 1995(Kenya Agricultural Research Institute, 1995) Kenya Agricultural Research Institute; Muriuki, A.W.; Kanyajua, S.M.; Kenya Agricultural Research InstituteIn 1995, a training workshop was convened by the Fertilizer use Recommendation Project (PURP) at the National Agricultural Research Laboratories (NARL) Kabele. It was held on the 8th and 9th February 1995 in the NARL, Conference room. The aim of this workshop was to inform and discuss with participants, the plans of the Fertilizer Use Recommendation Project within the Second National workshop was to inform and discuss with participants the plans of the Fertilizer Use Recommendation Project within the Second National Agricultural Research Programme (NAHP I I) (1995 - 1999). In 1994, FURP published site and crop specific fertilizer recommendations based on research findings from the fertilizer trials conducted by the project in the high and medium rainfall areas since 1987. The results which were published in districtwise fertilizer recommendation brochures, were circulated to the Fertilizer Extension Project (FEP) and the extension service of the Ministry of Agriculture, Livestock Development and marketing (MALDM) for verification. The first results obtained from on-farm verification/demonstration trials using FURP data were presented by FEP in the workshop. A background highlighting the project purpose, organisation and activities of FEP was also given.
